diff --git a/uki-editbootconfig.sh b/uki-editbootconfig.sh
index 97bae3a..6e35820 100755
--- a/uki-editbootconfig.sh
+++ b/uki-editbootconfig.sh
@@ -3,8 +3,8 @@ echo "###" "$0" "$@"
 
 # set arch-specific variables
 case "$(uname -m)" in
-    aarch64) arch="aa64"; ARCH="AA64"; uuid="b921b045-1df0-41c3-af44-4c6f280d3fae";;
-    x86_64)  arch="x64";  ARCH="X64";  uuid="4F68BCE3-E8CD-4DB1-96E7-FBCAF984B709";;
+    aarch64) arch="aa64"; ARCH="AA64"; uuid="b921b045-1df0-41c3-af44-4c6f280d3fae"; rootfs="2";;
+    x86_64)  arch="x64";  ARCH="X64";  uuid="4F68BCE3-E8CD-4DB1-96E7-FBCAF984B709"; rootfs="3";;
 esac
 
 # figure where shim.efi and BOOT.CSV are located
@@ -27,12 +27,12 @@ done
 
 # kiwi doesn't setup discoverable partitions, so fixup after the fact
 # here.  The UKI depends on that to find the root filesystem.
-#  * The image is loop-mounted.
-#    - partition #1 is biosboot (can this be disabled?).
-#    - partition #2 is the EFI ESP.
-#    - partition #3 is the root filesystem (this needs fixup).
+#  * The image is loop-mounted, partitions:
+#    - biosboot (on x86 only, can this be disabled?).
+#    - EFI ESP.
+#    - root filesystem (this needs fixup).
 echo "# hack: rootfs: $uuid"
-sfdisk --part-type /dev/loop0 3 "$uuid"
+sfdisk --part-type /dev/loop0 "$rootfs" "$uuid"
 
 # bz2240989: shim has a hard dependency on grub.  grub has a hard
 # dependency on dracut.  Ideally we would simply not install